Support for `sun4c' machines (e.g., SS2, SS1, IPC) was officially
dropped in Etch. I believe Sarge was already hardly installable on such
machines [0].
Support for SMP `sun4m' was dropped (well, largely unmaintained) in the
2.6 Linux kernel and is now slowly reappearing. However, AFAIK, it is
not yet considered stable. Thus, Etch won't have any `sparc32-smp'
kernel image [1]. 2.4 SMP kernels that came with Sarge do work, though.

2.4 kernels (after 2.4.21) are not stable on sparc32-smp. On all
sun4m-smp I have tested, they randomly hang with "watchdog reset".